Kevscar
You have mentioned the 24th but haven't said in your post which month that relates to. You might want to clarify for people reading who may be considering attending. Anyone with a Blue Badge who is applying for congestion charge exemption just needs to be aware that it can take a few weeks for the application to be processed.

For anyone in the UK who has a car that is also exempt from vehicle excise duty (road tax) by virtue of their disability then there is no need to make an advance application for congestion charge exemption. In fact, there is no need to do anything at all. The cameras used for the congestion charging regime are linked to the DVLA computer database so the exemption is automatically applied without you needing to do anything. Anyone with a Motability scheme car will be vehicle excise duty exempt. Others may have the exemption on a non-Motability vehicle if they have successfully applied for it.

Hope that is helpful.